Filesystem handling is now more flexible
- removed CResourceLoader class in favor of one that implements resource loader interface
- removed global pool of files, in favour of more dynamic approach
- renamed some files to match current situation
All these changes are needed mostly for future mod manager + .zip support

git-svn-id: http://svn.code.sf.net/p/vcmi/code/trunk/@3476 4dfc6b2a-8b31-0410-aa91-d6c70e3ac834